1. Field of the Invention
The present invention relates to a device for decantation deposition of cells on an analysis plate, said cells being contained in a cell suspension comprising a cell preservation liquid and said cells, said suspension being poured into a reception chamber which is placed above the analysis plate and the bottom of which is open and extends opposite a cell deposition area of the analysis plate, the bottom of the chamber being in fluid communication with an absorption material for the preservation liquid in order to absorb the latter gradually and to permit homogeneous decantation deposition of the cells onto the cell deposition area of the analysis plate, the absorption material being disposed about the cell deposition area, and the bottom of the reception chamber being set at a distance from the analysis plate in order to delimit, between it and the analysis plate, a path for fluid communication between the chamber and the absorption material.
The invention also relates to a sheet of absorption material used in such a device.
2. Description of the Related Art
The document EP-1 045 249, for example, describes a deposition device of this type. In this type of decantation deposition device, the cell preservation liquid starts to be absorbed into the absorbent material as soon as the cell suspension reaches the analysis plate. Such an absorption system results in the cells present in the suspension having a tendency to move towards the edge of the deposition area of the analysis plate since they are dragged along by the preservation liquid, if the absorption of the latter is too rapid. Cell deposition is not then homogeneous on the deposition area, thereby causing a problem for the subsequent analysis of the deposit.
In order to remedy this drawback, a deposition device has been proposed in which the absorbent material is lightly pressed by a member for clamping and holding the absorbent material, which, in a first stage, slows down the absorption of the preservation liquid and permits vertical, homogeneous decantation of the cells. In a second stage, the absorbent material is released and the absorption of the preservation liquid is then accelerated. However, such a device requires a long decantation time for the cell suspension and in addition requires handling of the clamping member during decantation, thereby complicating the process of obtaining the cell deposit.
Other deposition devices propose the use of centrifuging to accelerate cell deposition on the analysis plate. The document U.S. Pat. No. 5,318,749 describes such a device for deposition of cells by centrifuging. However, a centrifuging device is complex, bulky, expensive and not very convenient to use. In addition, such a device cannot easily be integrated in an automated line for obtaining cell deposits, owing to the high speed rotation of such a device. Moreover, centrifuging has a tendency to plicate the cells present in the cell suspension since they are crushed on the analysis plate during centrifuging.